'Why is flu season so early this year?' — free shots now cover up to age 14, but check stock before you go

Suspected cases among elementary school children have surged sharply, triggering an early epidemic alert

Vaccination eligibility expanded to age 14, schedule moved up — children's shots begin Monday

WHO strain changes cut supply — health authorities urge checking availability before Chuseok

Children wait to be seen at a hospital in Seoul. This file photo is unrelated to the article. [Yonhap]

South Korea is on high alert as influenza has arrived well ahead of winter, spreading across the country earlier than usual.

A nationwide flu epidemic alert was already issued on Sept. 11. Health authorities have responded by moving up the National Immunization Program schedule by up to a week compared with previous years and expanding free vaccination coverage to children up to age 14.

This year, however, supply is tight. The WHO's decision to replace all recommended strains for the Northern Hemisphere flu vaccine has cut the total domestic vaccine supply by about 4 million doses from last season, making it essential for people to check stock availability before visiting a clinic.

Cases up 3.8 times from last year — school-age children hit hardest

Sentinel surveillance data from the Korea Disease Control and Prevention Agency show that influenza-like illness cases reached 25.3 per 1,000 outpatients at primary care clinics in week 36 (Aug. 30–Sept. 5). The figure has climbed steeply for four consecutive weeks, rising from 7.5 in week 33 to 9.2 in week 34, 13.3 in week 35 and 25.3 in week 36.

That is more than 3.8 times the 6.6 cases per 1,000 recorded during the same period last year. Last year, the count did not reach 22.8 until week 44 — early November — yet this year it has already surpassed that level in early September.

Hospital inpatient numbers have risen at the same pace, climbing from 78 in week 33 to 300 in week 36 — a 3.8-fold increase in four weeks.

Children aged 7 to 12, who live and study in close-contact settings, recorded the highest influenza-like illness rate of any age group at 75.1 per 1,000, far ahead of infants and toddlers aged 1 to 6 at 49.8 and teenagers aged 13 to 18 at 31.3.

Adding to the concern, the COVID-19 detection rate among respiratory illness samples has also risen for four straight weeks, from 9.1 percent in week 33 to 16.3 percent in week 36, raising fears of a fall "twindemic" — a simultaneous outbreak of flu and COVID-19.

[Korea Population, Health and Welfare Association]

Free shots extended to age 14 (born 2012) — vaccinations roll out in stages from Monday

With flu season arriving earlier than expected, the KDCA has moved up the entire National Immunization Program schedule.

The most significant change is the expansion of the free vaccination age range. Starting with the 2026–2027 season, eligibility has been extended from the previous "6 months to 13 years" to include children up to age 14 — specifically those born between Jan. 1, 2012 and Aug. 31, 2026. The change brings first- and second-year middle school students into the free vaccination program, strengthening protection against group transmission among school-age children.

The start date has also been moved up. The single-dose schedule for children, originally set for Sept. 28, has been brought forward by a week to align with the two-dose schedule. All children aged 6 months to 14 years and pregnant women will be able to receive their shots starting Monday.

For older adults, those aged 75 and above (born before 1951) will begin vaccinations on Oct. 6, moved up from the original date of Oct. 12. Those aged 70 to 74 will follow on Oct. 12, and those aged 65 to 69 on Oct. 15.

High-risk groups, including immunocompromised individuals, may receive vaccinations from Oct. 6 regardless of age. Long-term care hospitals and facilities housing vulnerable populations will begin vaccinations as soon as doses arrive.

Total supply down 4 million doses — tight stocks draw warning from medical community

The central concern this season is vaccine supply. The WHO's recommended composition for the Northern Hemisphere quadrivalent influenza vaccine has been completely overhauled from last season, with all major strains — influenza A (H1N1 and H3N2) and influenza B (Victoria) — replaced.

Cultivating the new strains and optimizing production has reduced manufacturing yields, cutting total domestic vaccine production and imports by about 4 million doses compared with last season.

On top of that, a delay in early deliveries from Sanofi prompted the government to make an emergency substitution, replacing 500,000 doses in its procurement contract with products from GC Biopharma.

The KDCA says it has secured 12.33 million doses through government procurement for the National Immunization Program, with an additional 370,000 doses procured for private-sector use, and maintains that the national program will proceed without disruption. Even so, the buffer in the private distribution market is considerably smaller than in previous years.

The Korean Medical Association's Committee on Infectious Disease Response called on authorities to act proactively. "Concerns from the medical community about vaccine and treatment supply continue to mount," it said, urging the government to "monitor supply and distribution conditions in advance and do everything possible to ensure vaccines reach patients in a timely manner."

Check remaining stock before you visit — consider getting flu, COVID-19 and pneumococcal shots together

Given delivery schedules at individual clinics and the logistics challenges posed by the upcoming Chuseok holiday (Sept. 24–26), temporary shortages at specific facilities cannot be ruled out if demand concentrates in certain locations early on.

Health authorities are urging the public to check vaccine availability and stock in advance — either through the KDCA's vaccination information website or their local public health center — before visiting a clinic or contracted medical institution.

Those visiting vaccination sites should bring the required documentation: a family register or national health insurance card for children, a maternal health record book for pregnant women, and a government-issued ID for older adults. After receiving a shot, recipients should remain on-site for 20 to 30 minutes to be monitored for acute adverse reactions before leaving.

Experts advise getting vaccinated before the outbreak intensifies. Flu typically presents with high fever above 38 degrees Celsius, headaches and muscle pain, but older adults and immunocompromised individuals may show atypical symptoms — loss of appetite, lethargy or reduced consciousness — without fever, requiring close observation.

Kim Eun-jeong, an internal medicine physician at the Korea Population, Health and Welfare Association's family health clinic, said prevention before an outbreak is far more important than responding after one begins. "People eligible for the National Immunization Program should check the vaccination schedule as soon as possible," she said. "Even those not covered by the program should consult a doctor and seriously consider paying for a shot based on their own health condition."

She added that getting the flu shot alongside COVID-19, respiratory syncytial virus and pneumococcal vaccines at the same visit is "an effective way to guard against serious complications from respiratory illness."

silverpaper@heraldcorp.com